From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756260AbcB0Iw4 (ORCPT ); Sat, 27 Feb 2016 03:52:56 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:41957 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755533AbcB0Iwz (ORCPT ); Sat, 27 Feb 2016 03:52:55 -0500 Date: Sat, 27 Feb 2016 00:52:46 -0800 From: Christoph Hellwig To: Yang Shi Cc: gregkh@linuxfoundation.org, tj@kernel.org, lizefan@huawei.com, tglx@linutronix.de, rostedt@goodmis.org, bigeasy@linutronix.de, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, linaro-kernel@lists.linaro.org Subject: Re: [RFC V2 PATCH] kernfs: create raw version kernfs_path_len and kernfs_path Message-ID: <20160227085246.GC26010@infradead.org> References: <1456523259-8588-1-git-send-email-yang.shi@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1456523259-8588-1-git-send-email-yang.shi@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 26, 2016 at 01:47:39PM -0800, Yang Shi wrote: > commit 5634cc2aa9aebc77bc862992e7805469dcf83dac ("writeback: update writeback > tracepoints to report cgroup") made writeback tracepoints report cgroup > writeback, but it may trigger the below bug on -rt kernel since kernfs_path > and kernfs_path_len are called by tracepoints, which acquire sleeping lock. Sounds like the tracepoints simplify shouldn't try to do this path generation at all..